1. Field of the Invention
This invention relates in general to steam traps and the monitoring of steam traps.
2. Description of Related Art
Steam traps are equipment items common in factories, refineries and other industrial or commercial facilities that use steam line systems. Steam traps are installed in process steam lines and act to separate condensed steam, or “condensate,” from the steam without allowing the steam to escape from the steam line system. The separated condensate is then typically recycled through condensate return lines to a boiler for conversion back to steam. During ideal operation, a steam trap removes condensate from process steam lines while preventing steam from escaping past the steam trap into the condensate return lines. If steam is allowed to pass through the steam trap into the condensate return lines, the result is a loss of valuable energy and a reduction in the efficiency of the steam line system. Further, if the steam trap is not removing condensate from the steam line system, and the condensate is allowed to remain in the steam lines, condensate return lines, the result is a loss of valuable energy and a reduction in the efficiency of the steam line system. Further, if the steam trap is not removing condensate from the steam line system, and the condensate is allowed to remain in the steam lines, the result is a reduction in the efficiency of the steam system and an increase in the needed energy to maintain the same operations.
There are several well-known types of steam traps, including inverted bucket traps, float traps, thermostatic traps, and disc traps. Manufacturing facilities, refineries, and large buildings often are fitted with extensive systems of steam lines for heating and for process steam. Some of these facilities typically contain 1,000 or more steam traps. To promote efficient operation of the steam traps, some type of monitoring or inspection is often employed to detect malfunctioning traps, which may then be replaced or repaired.
Several different methods of monitoring the condition of a steam trap are known. One method uses a system with a battery powered probe to sense the temperature of a trap. The temperature measurement is then correlated with a particular condition of the steam trap. Another method uses a system with a battery powered probe in an inverted bucket steam trap to sense the presence of water in the trap. When the inverted bucket steam trap has water in it, the trap has a state or condition referred to as “prime.” A properly operating inverted bucket trap must have a condition of prime if it is functioning properly. A requisite amount of water in the trap is indicative of proper steam trap operation. Such a steam trap monitoring system includes a probe extending into a steam trap, the probe being responsive to the level of condensate in the steam trap.
Another method of monitoring a steam trap uses a steam trap system including signal lights on the steam trap indicative of the process conditions in the trap. For proper monitoring, such a system requires visual inspection of the steam trap.
Another method to monitor a steam trap uses a hard wired system, which includes physical wiring that is threaded from a steam trap to a centrally located steam trap control station for receiving and storing data concerning the process conditions of the steam trap.
Still other methods for monitoring steam traps use systems suitable to transmit and report steam trap status data using radio wave signals.